LeetCode 557. Reverse Words in a String III (反转字符串中的单词 III)

Given a string, you need to reverse the order of characters in each word within a sentence while still preserving whitespace and initial word order.

Example 1:

Input: "Let's take LeetCode contest"
Output: "s'teL ekat edoCteeL tsetnoc"

Note: In the string, each word is separated by single space and there will not be any extra space in the string.

---

题目标签：String

　　题目给了我们一串string，让我们把每一个word 给reverse一下。

　　设p1 和 p2，每一次让p2 找到 “ ” space，然后 reverse p1 和 p2 之间的 word，然后更新p1 和 p2 的值。

　　具体请看code。

Java Solution:

Runtime beats  96.43%

完成日期：05/31/2018

关键词：Two pointers

关键点：反转p1 和 p2 之间的 word

 class Solution
 {
     public String reverseWords(String s)
     {
         char [] arr = s.toCharArray();
         int p1 = 0;
         int p2 = 0;

         while(p1 < arr.length)
         {
             // let p2 find the space
             while(p2 < arr.length && arr[p2] != ' ')
                 p2++;

             // once p2 find the space, do reverse between p1 and p2
             int left = p1;
             int right = p2 - 1;

             while(left < right)
             {
                 char temp = arr[left];
                 arr[left] = arr[right];
                 arr[right] = temp;

                 left++;
                 right--;
             }

             // reset p1 p2
             p1 = p2 + 1;
             p2++;

         }

         return new String(arr);
     }

 }

参考资料：n/a

LeetCode 题目列表 - LeetCode Questions List

题目来源：https://leetcode.com/